11.3.2 Packages

A project file may contain packages. The name of a package must be one
of the identifiers from the following list. A package
with a given name may only appear once in a project file. Package names are
case insensitive. The following package names are legal:

Naming

Builder

Compiler

Binder

Linker

Finder

Cross_Reference

Eliminate

Pretty_Printer

Metrics

gnatls

gnatstub

IDE

Language_Processing

In its simplest form, a package may be empty:

project Simple is
package Builder is
end Builder;
end Simple;

A package may contain attribute declarations,
variable declarations and case constructions, as will be
described below.

When there is ambiguity between a project name and a package name,
the name always designates the project. To avoid possible confusion, it is
always a good idea to avoid naming a project with one of the
names allowed for packages or any name that starts with gnat.